High voltage power transmission lines carrying voltages in the hundreds of kilowatt range have been constructed to extend from spaced towers or poles in terrain which is often practically inaccessible to land vehicles. In recent years, a number of methods and devices have been developed to facilitate the repair and maintenance of high voltage power transmission lines which are accessed by helicopter.
Helicopter transported landing platforms and work scaffolds which can be attached to the cross arm of a utility pole have been developed to permit a lineman to disembark from a helicopter and descend vertically along the utility pole to the power transmission lines supported thereby. Such devices are heavy and bulky, and must be suspended from and transported by a helicopter. The helicopter, with the suspended load, must be deftly maneuvered by the pilot, frequently with the assistance of helicopter crewman, to position and remove the landing platform and work scaffold from the arms of the utility pole. The operation of a helicopter with heavy platforms and scaffolding hanging below the helicopter in the vicinity of high voltage power transmission lines is a risky and dangerous undertaking, particularly in windy conditions.
Accordingly, there exists a need for a landing platform which may be safely emplaced on the utility pole, without need for extensive and dangerous helicopter maneuvering and, preferably, by a single lineman, which can be used to safely transfer a lineman from the helicopter to the utility pole and to support the lineman's equipment while he is on the pole.